A conventional wrench 10 is shown in FIG. 1 and generally includes a shank 12 with an box end 11 and an open end 13. The shank 12 is made of solid metal so as to bear large torque when operating the wrench 10. However, such the solid shank 12 is heavy and is not convenient for the user to carry and/or operate. Generally, the user will carry a whole set of wrenches having plural of specifications so as to tighten or loosen different buts or bolts. The whole set of wrenches is so heavy that the applicant expects to develop a new and useful wrench that has light weight and the structural strength is properly maintained.
The present invention intends to provide a wrench having a shank with a plurality of recesses defined in two surfaces thereof and ribs are formed to divide recesses so as to maintain the strength of the shank of the wrench.